Fiber optic cables are used for transmitting light pulses and have become particularly useful for communications transmission. Fiber optic cables are also increasingly used to replace copper wire in computers and other high speed electronic applications where optical switches (transphasors) are used instead of transistors. This is because light transmits signals faster and more efficiently than electrons in wire.
In most cases fiber optic cables comprise single or multiple flexible light guides. These light guides are capable of transmitting a light impulse from one end of such a cable to its distant end with little distortion or loss of light intensity. This is because fiber optic cables are unaffected by electrical or magnetic interference that degrades electrical signals carried by copper conductors. Further, fiber optic cables are much lighter and much less expensive to manufacture than electrically conductive metal cables. For these reasons fiber optic cables and their associated devices have become much more common in recent years and will continue to grow in use.
As fiber optic systems have developed, fiber optic cables terminated with standard connectors have become more common. These connectors make it possible to join interchangeable fiber optic cables with each other and their associated devices. Typically, these connectors are conical plastic plugs into which the light guide or guides from the cable are embedded in predetermined positions that mate with a receptacle or a second connector.
Some drawbacks to the uniform use of such fiber optic cables with connectors are related to the fragility of the fiber optic cables and the interfaces of connectors with the fiber optic cables. If the fiber optic connectors are allowed to move freely while the fiber optic cable is restrained it is relatively easy to damage the fiber optic cable and cause fractures in the cable which would result in loss of signal. The connectors can also suffer from damage to their optical surfaces if not properly protected.
It is for these reasons that new storage devices have been designed for storing and shipping fiber optic cables complete with their connectors. An example of such a storage device is found in U.S. Pat. No. 4,387,863 to Edmonston et al. The Edmonston patent discloses a spool storage device in which two additional flanges are added to the two standard flanges normally found at spool ends. These additional flanges form channels with the standard flanges that act as seats for the connectorized ends of the fiber optic cable. The channels communicate with the surface of the spool hub via grooves in the standard flanges. In this manner the connectors can be wedged in the channels and restrained from movement. The Edmonston device is an improvement over the state of the art in which connectors had to be manually tied down on the spools to prevent their movement and possible damage to the cable.
The Edmonston device does not, however, completely solve the problems inherent in storing fiber optic cable. The channels provided on each end of the Edmonston spool only allow wedging of the cable connectors. Rotation of circular spools may free the connectors due to their inertia and centrifugal acceleration. Merely wedging the connectors therefore does not positively lock the fiber optic cable and connectors in place. While Edmonston's use of a groove, to prevent bending of the cable during the stowing of the cable ends, is an improvement over the prior art, the channels into which the connectors are wedged do not protect the connector ends from dirt and debris that might damage the optical surfaces on the connector end.
In view of the above it is an object of the present invention to provide an improved fiber optic cable storage device that protects connectors and the fiber optic cables from damage, provides for easy stowing of the fiber optic cables and is relatively inexpensive to produce.